For N52FN, N62FN, N79RH, N79WW, N80SB, N80SBM, N88RH, N88WWB, N90PT, N95RHN. A slower valve which reduces skipping, and recoil induced second cycling.
The trigger mechanism actuates the trigger valve inside the gun when you pull it, which fires the driver and drives the nail/staple. There are two types of triggers: “sequential” and “contact”. Contact triggers allow you to “bump fire” the gun: just hold the trigger down and fire multiple nails at a time. Sequential triggers require you to first press the nose to the medium before the gun will fire, so it allows you to fire only one nail at a time.